The present invention relates to a cover structure for a wireless communication device arranged at least partly as a standard expansion card, and the cover structure being provided with at least one cover surface. The invention relates also to a method in the manufacture of a cover structure for a wireless communication device arranged at least partly as a standard expansion card, and wherein the cover structure is provided with at least one cover surface. The invention relates further to a wireless communication device arranged at least partly as a standard expansion card and comprising at least one cover structure provided with at least one cover surface.
According to prior art, for example portable personal computers (PC) are often provided with an expansion card interface in which a standard expansion card can be linked. These expansion cards have a size and shape of nearly a credit card, and they are intended for forming a functional unit with the PC. Such expansion cards include memory cards (RAM and ROM cards), modem cards and various input/output cards (I/O cards) as well as hard disk cards. Expansion cards can also contain a transmitter/receiver with its antenna for radio communication, wherein the PC can, by means of this card-like wireless communication device, be in a data transmission connection with other devices or with a data communication network, such as a local area network (LAN).
One known expansion card is a PC card according to the PCMCIA (Personal Computer Memory Card International Association) standard. The PCMCIA standard defines also the physical size of the PC card, wherein according to the PCMCIA standard the length of the PC card is 85.6 mm and the width is 54 mm. PC cards are further divided into three types, wherein the thickness of the PC card can be 3.3 mm (type I), 5.0 mm (type II) or 10.5 mm (type III). PC cards are arranged to be inserted entirely inside the PC, but so-called extended PC cards can be even 40 mm longer than regular PC cards. These extended PC cards are placed partly outside the PC, wherein the thickness and shape of the PC cards can vary in this projecting part outside the PC. This part can be used for example for the placement of the antenna of the wireless communication device.
One known card-like wireless communication device comprising a transmitter/receiver with its antenna is Nokia Cellular Card Phone, i.e. a card phone which can be coupled to expansion card interfaces of types II and III of the PC card according to the PCMCIA standard. This card phone can be for example a mobile station (MS) according to the GSM (Global System for Mobile Communication) standard, wherein the PC in which the card phone is installed can be in wireless data transmission connection with base stations (BS) of a public land mobile network (PLMN) by means of radio waves.
To secure the undisturbed function of components, such as integrated circuits (IC), arranged inside the card-like wireless communication device, usually on a circuit board, they must be protected from interference caused e.g. by the electromagnetic field of the antenna, such as induced disturbance signals. Malfunctions can also be caused by electromagnetic fields emitted by radio-frequency (RF) and particularly microwave frequency signals moving from one location to another between components and on the circuit board by means of wires. Further, clock signals for controlling the components and to be transmitted by means of wires are also susceptible to disturbance signals. According to prior art, e.g. inside the above-mentioned card phone there is a flexible and electroconductive sealing used for shielding and which preferably forms a tight RF sealing when being pressed against the cover structures of the card phone.
The RF sealing exerts a force on the cover structure of the card-like wireless communication device, resulting in the bending of the cover structure and particularly warping of its wide planar cover surfaces. As a result of the bending, the thickness of this card-like wireless communication device is increased and it does not fit e.g. in the expansion card slot according to the PCMCIA standard or in the space reserved for the expansion card. Inserting the card-like wireless communication device by forcing it into the space reserved for it may result in mechanical damage of the cover structure or the sealing of the card, or sticking of the card in the expansion card slot.